Journal of Natural Disaster Science

LONG-PERIOD RESPONSE SPECTRA FROM NONLINEAR SLOSHING ANALYSIS UNDER HORIZONTAL AND VERTICAL EXCITATIONS

Yoshikazu YAMADA
Professor, Department of Civil Engineering, Kyoto University, Kyoto
Hirokazu IEMURA
Associate Professor, Department of Civil Engineering, Kyoto University, Kyoto
Shigeru NODA
Instructor, Department of Civil Engineering, Kyoto University, Kyoto
and
Saburo SHIMADA
Manager, Technical Research Institute, Maeda Construction Co., Ltd., Tokyo

(Received 10 July, 1987 and in revised form 28 November, 1987)

Abstract

The effect of nonlinear boundary conditions at the liquid surface on the sloshing heights in cylindrical tanks under horizontal and vertical ground motion is discussed and compared with data obtained by linear analysis. This effect depends mainly on both the dimensionless sloshing height and the dimensionless liquid depth, as far as a small sloshing height is concerned. A simple formula for estimating this effect is proposed. On the basis of the large sloshing heights recorded during the 1983 Nihonkai-chubu earthquake, the sloshing heights under nonlinear conditions are estimated to be about 10-25% larger than those calculated under linear conditions. Taking this into account, the response spectra of relatively long-period ground motions deduced from the recorded sloshing heights are nearly equal to the two-dimensional response spectra calculated from strong-motion seismograms.

Key words

long-period response spectra, nonlinear sloshing analysis, simultaneous exitations in horizontal and vertical directions, the 1983 Nihonkai-chubu earthquake